a) Đk \(x\ge\frac{1}{2}\)
\(\sqrt{2x-1}=\sqrt{5}\Leftrightarrow2x-1=5\Leftrightarrow x=3\)
b)
Đk \(x\ge5\)
\(\sqrt{x-5}=3\Leftrightarrow x-5=9\Leftrightarrow x=14\)
c) Đk \(x\ge1\)\(\sqrt{9\left(x-1\right)}=21\Leftrightarrow9\left(x-1\right)=441\Leftrightarrow x-1=49\Leftrightarrow x=50\)d)
\(x\ge0\)
\(\sqrt{2x}-\sqrt{50}=0\Leftrightarrow\sqrt{2x}=\sqrt{50}\Leftrightarrow2x=50\Leftrightarrow x=25\)